Updated at 6:50 a.m. ET: LONDON -- An athlete steps up to take his throw -- except he is holding a missile, not a javelin; a pole vaulter soars high, but seems headed for a landing on a moldy mattress; an Olympic mascot's leg attracts some unwanted attention from a passing dog.

While at least four graffiti artists have been arrested by police ahead of the Games -- then released on bail conditions designed to prevent them from making their mark near the venues -- London is full of art works ranging from crude and comical to heavy satire to straightforward celebration.

A piece by artist Jimmy C. is among the latter, a large spray-painted mural of Jamaican sprinter Usain Bolt's face with streaks of vibrant color radiating outwards on the side of a row of houses in Shoreditch, not far from the Olympic Park.

He could only afford the $1,500 cost of the painting after he sold more conventional artworks at a gallery show in Paris, France, and had some money left over from paying his rent.

"People pick up on a spiritual narrative in my paintings," he told NBCNews.com, explaining that when he went through art school painters like Caravaggio and Velazquez were among his favorites and may have influenced his work.

“Some street art is very quick, humorous and political … I try to create more lasting things with human qualities that everyone can identify with," he added.

'A very charismatic guy'East London resident Jimmy Cochran, 39, as he is known in ordinary life, admitted he didn't know too much about the Olympics before deciding to paint something. He said he'd asked friends in Britain and Australia, where he grew up, what they thought about the Games.

“He [Bolt] kept coming up in more ways than one,” he said. “I thought ‘OK, this is interesting.’ I looked him up online, looked at images of him and realized he was a very charismatic guy, a big personality. I was drawn by his features.”

He painted the image on a wall often used by street artists, but didn't ask permission from the owner, who Cochran said he had been told was in Greece.

He has always tried to keep his identity a secret, although the Daily Mail newspaper has claimed to have identified him and published a photograph that it said was believed to be him.

Banksy's piece showing a javelin thrower carrying a missile is entitled "Hackney [an East London borough] welcomes the Olympics," while the pole vaulter image is called "Going for Mold," according to a spokeswoman for the artist.

His spokeswoman, of Banksy's Pest Controloperation, said the images did exist in the real world, but refused to say where they were.

A dispute with a London graffiti legend known as King Robbo and perhaps some jealousy at Banksy's success mean some graffiti artists will paint over his work where they can find it, a London street art source told NBCNews.com.

For other street artists, the risk is mainly from the authorities.

Corporate clown lasted six daysAn artist known as Mau Mau painted an image of Ronald McDonald with sponsors' names on his costume and an Olympic torch belching out black smoke over the Olympic rings on a wall in Ealing, West London. The local authorities painted over it six days later, he told NBCNews.com, despite the wall belonging to a friend of his.

In 1940 and 1941 Adolf Hitler had vowed to break London's resolve by targeting the factories and warehouses in the East End. But the land that had once been pulverized is now home to a thriving financial center and the London 2012 Olympic Park. NBC's Brian Williams reports.

Mau Mau said he came up with the idea after the Olympic torch relay went past his studio in the Devon area of western England and he "could barely see the torch" because of trucks emblazoned with corporate logos.

"I love to watch sport," Mau Mau said, refusing to give his real name. "I love to see Usain Bolt run the 100 meters … It's lovely to see lots of countries together competing.

"I don't see that as negative at all, it's more the branding side of things. I think it should be run more ethically… it should be more for the people and less about huge corporations," he added.

Teddy Baden, 32, painted the image of one of the Olympic mascots and the overly amorous dog to poke fun at the Olympics in a "non-malicious" way, he said.

"It becomes such a serious thing sometimes," he said, adding that he hoped the image would appeal to the "English sense of humor."

London has become a giant melting pot of cultures and nationalities, but it's not immediately apparent to tourists. The double-dip recession has hit diverse neighborhoods especially hard. NBC's Stephanie Gosk reports.

"We always support the underdog in sport, and we can take a pop at things and have a laugh at ourselves ... it's just a bit of fun," he said.

'Welcome to London, it's gray'Lee Bofkin, co-founder of Global Street Art, which finds walls that artists are allowed to paint and keeps an archive of images, told NBCNews.com that the "vast majority of [street] art has been satirical, sending up the Olympics, noting its heavy-handed corporate presence, and just sort of generally poking fun."

He expressed disappointment that some art had been painted over, citing a wall in Plaistow, East London, a popular spot for street artists that was until recently covered with art.

"A few weeks ago, it was completely painted gray," Bofkin said. "It's a shame. We're saying to tourists 'Welcome to London, it's gray,' rather than 'Welcome to London, it's colorful.'"

An actor from gangster movie "Lock, Stock and Two Smoking Barrels" is giving walking tours of old underworld haunts in East London, where this month's Olympic Games are being held. NBC's Theresa Cook reports.

“What we have a problem with is low-grade ‘tagging,’ that kind of graffiti … that’s just horrible and makes places look unloved,” Helen Bingham, a spokesperson for the group, told NBCNews.com. “We have less of a problem with Banksy-esque street art.”

She said ultimately local people should decide if they wanted an image preserved or removed, but admitted it was a tricky subject.

“One person’s art is another person’s abomination … of all the issues we deal with, it’s the most difficult," Bingham said.